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Practice nursing basics - warts

Thomas F Poyner
MB BS FRCP(Lond) FRCP(Glasg) MRCGP DPD
GP and Hospital Practitioner
Queen's Park Medical Centre
Stockton-on-Tees

Founder member
Primary Care Dermatology Society

E:thomas.poyner@gp-a81002.northy.nhs.uk

Warts are ubiquitous and are now thought not to be more frequent in patients with atopic eczema. However, transplant patients who are on immunosuppressants are more prone to warts, and their lesions tend to be more extensive. Swimming pools provide antiseptic footbaths to try to prevent superficial skin infections, but these are probably of little benefit with regard to verrucae. Verruca socks are frequently recommended to try to prevent the spread; however, these are probably ineffective, and one should note that hand warts are left uncovered. Warts can also develop in scars, known as the Koebner phenomenon.

Different types of warts
The appearance of a wart depends on the site of the lesion and the particular strain of the virus (see Figure 1). Common warts present as multiple flesh-coloured lesions that have a rough surface. They are usually found on the hands. Plane warts are smaller, flat-topped and found on the back of the hands and face. The surface of a plane wart looks dull and is rough to the touch. Filiform warts are long thin conical lesions, commonly found around the nose.
Verrucae or plantar warts, are found on the plantar surface of the feet. They are not elevated like the lesions on the hands because the wart is "pushed in" by the pressure on the foot. Verrucae have a rough surface and a collar of hyperkeratosis. When verrucae join together they form a mosaic wart. All the previously mentioned warts can arise on the genitalia along with genital warts. Genital warts can vary in size, shape and colour. They also tend to have a rough surface.

[[nip10_fig1_29]]

The differential diagnoses
Corns are hyperkeratosis that occur at sites of ­pressure. One can tell the difference between a corn and verruca by the fact that the verruca has thrombosed blood vessels. On paring down a lesion, if it is a verruca one sees tiny black dots, which bleed. Verrucae are tender when squeezed with sideways pressure, while corns are tender only on direct pressure.
Molluscum contagiosum presents as pink umbilicated papules. They are of viral aetiology and are more common in those with atopic eczema. They can become secondarily infected and inflamed.
Seborrhoeic warts, otherwise known as basal cell papillomas, present as pigmented well-defined lesions, with a rather stuck-on appearance. They are not of viral aetiology but are associated with age and sun exposure.
Pitted keratolysis presents as shallow pits in the plantar surface of the feet. There is often an odour associated with the rash. Pitted keratolysis responds to oral and topical antibiotics (eg, oral erythromycin or topical fusidic acid). Trauma from sport can result in haemorrhages over the heels, and this rash is known as talon noire.
Skin malignancy comes into the differential diagnosis of warts, especially for the older patient. A cutaneous horn can be the result of a viral wart, an actinic keratosis or a squamous cell cancer. A squamous cell carcinoma can also present as a nodule. If there is any question over the diagnosis then it is worth sending for histology; the lesion can be excised or curetted under local anaesthetic and all the tissue sent for histology. One should always have a high index of suspicion when an elderly patient presents with a "solitary" lesion.

Natural history
If left untreated, approximately two-thirds of warts resolve spontaneously within two years. Warts can look unsightly and occasionally be painful. However, left untreated, warts do no harm and clear without scarring.

Treatment of warts
A lot of time, energy and money can go into treatment. One can create one's own demand. The pharmacist can advise and treat many patients with over-the-counter (OTC) products. Most patients who do want active treatment can be treated in primary care. Compliance can be poor. One can try to treat all of a patient's warts, or treat a few and try to stimulate ­natural immunity. Genital warts are probably best referred to a genitourinary clinic, where the patient can be screened for other sexually transmitted ­diseases.

Topical treatments
Topical treatments are firstline therapy for warts on the hands and feet; however, they should not be used on facial warts. Salicylic acid is a very effective treatment for warts and verrucae. It acts as a keratolytic. The wart or verruca needs to be pared down at regular intervals to remove the excess keratin. Failure to remove excess keratin is a frequent cause of treatment failure. Salicylic acid needs to be applied carefully, once or twice daily depending upon the formulation. It can irritate and damage normal skin, but this can be protected by the prior application of petroleum jelly (such as Vaseline). Salicylic acid is available as a paint application, gel or ointment. Treatment should be tried initially for three months. Alternatives to salicylic acid are glutaraldehyde, formaldehyde and silver nitrate.
Patients and families should be advised how to use topical preparations, and this should be reinforced by referring to the patient information leaflet. An example of a treatment regimen would involve using a proprietary gel containing a combination of salicylic acid and lactic acid. First soak the wart; then apply one or two drops of gel. The gel sets to form a plastic coating over the wart, and no dressing should be applied. Next morning the elastic film should be removed and the gel reapplied. The wart can be abraded between applications.
Genital warts can be treated by the careful application of podophyllin, which needs to be performed by someone skilled in its use. Newer preparations that can be applied by the patient in certain circumstances include podophyllotoxin. Podophyllin and related compounds should not be used during pregnancy or while breastfeeding as they are cytotoxic. Imiquimod has recently become available for treating genital warts. It is an immune response modifier and is available as a cream formulation.

Cryotherapy
Cryotherapy provides a secondline alternative for the treatment of warts on the hands and feet. It can also be used as a firstline therapy for facial warts. The freezing and thawing of warts can speed their resolution, but cryotherapy is not a magical cure and is not suitable for young children.
One can either use the cotton bud technique or a cryospray. The cotton bud technique involves dipping a loosely wrapped cotton wool bud into a small receptacle of nitrogen. One has to use new equipment for each patient to stop the spread of viral infections. The spray technique involves using a more expensive piece of kit that enables the operator to direct a more precise jet of liquid nitrogen onto the wart.
The wart is frozen until a halo develops around it. Convention is to use a single freeze-thaw cycle for warts on the hands and a double freeze-thaw cycle for verrucae. One frequent reason for treatment failure is not removing excess keratin from the lesion before freezing. Cryotherapy can be repeated approximately every three weeks. However, one has to remember that one is treating a benign lesion that will probably resolve in spite of rather than because of medical interference.
Cryotherapy can cause pain and complications - the process of cryotherapy can be very similar to frostbite! Blistering can result, so it is wise to be cautious during the first treatment to see how the patient and their skin react. Little is lost as one is not dealing with a malignant lesion. Cryotherapy to periungual warts can damage the nail matrix. Melanocytes are very sensitive to cryotherapy, and pigmentary damage can easily occur on pigmented skin. Tendon damage can also occur.

Other therapies
Trying to remove warts by curette and cautery can be successful, although warts can reform in the scar. Lasers have been used to treat warts but are expensive and facilities are limited. Vaccines may exist in the future but at present are not a reality. Alternative treatments include herbal remedies, homeopathy, hypnotherapy and folklore remedies.

The final word
Referrals for warts are often the result of parental pressure. Patients and parents need to be reassured that warts left untreated will resolve without scarring and that there is no question of malignancy. The more warts a child has, the more daunting the task to try to provide active treatment and the less likelihood of success. Most therapies can be provided in a modern practice. Maybe in the future those practices that do not have extensive facilities will be able to refer their patients to intermediate care. However, we should always question whether active treatment is really in the best interests of the patient.